"Byron's 'Impromptu on a Recent Incident': A New Text of a Regency Squib" presents a new, superior text of a poem by Lord Byron.  According to Jerome J. McGann's Oxford edition of Byron's Complete Poetical Works, the earliest appearance of the four lines was in an 1816 American edition of Byron's works, where it was claimed that they were an unused stanza from "Lines to a Lady Weeping."  My article reveals that the lines were in fact a complete, unsigned poem that appeared in the Morning Chronicle on 6 March 1812 under the title "Impromptu on a Recent Incident."  The poem was therefore the second in a series of three anonymous political squibs that Byron published in the Chronicle that week.  I provide the new text of this significant poem and explain its subject and political motivation, giving an overview of the Whig anti-Regent "squib-warfare" that took place, mainly in the pages of the Morning Chronicle, in the early months of 1812.  I suggest that there may be additional anonymous poems in this newspaper by Byron (as well as other prominent poets) still to be indentified.